1. Field of the Invention
The present invention relates to the production of hydrocarbons, such as gas, condensate and oil, from a subsurface production formation. More particularly, the present invention is effective in a well formation having a lack of pressure,wherein two-phase flow velocity is insufficient to carry upwardly the liquid hydrocarbon phase from the bottom of the well. The device of the invention can be installed into the well without any reconstruction of the well bore. The invention avoids the use of artificial gas injection to promote the production of subsurface liquid hydrocarbons.
2. The Prior Art
In a method for enhancing production from a wellbore, the well exploitation frequently becomes complicated because of the liquid accumulation at the bottomhole. This accumulated liquid is the reason for the pressure drop within the tubing; it causes a decreasing of the well production and can eventually cause the complete shut down of the well. To avoid these mentioned problems, a number of the technological recovery processes have been used. Such recovery methods include three general procedures in this technology.
In the first recovery method, there is the release and removal of the liquid from the well bottom by lifting it to the surface using various pumps. Also, the gas velocity is maintained within the tubing higher than the critical velocity by the diminution of the tube diameter. Plunger lift and different foam creating chemicals may be used. Then the dispersion flow is improved by use of a mechanical treatment or a heat treatment.
In the second recovery method, there is the release and removal of the liquid from the well bottom by pumping from the formation pay zone. Instead the process has a gas or aqueous liquid fluid injection step into the engrossed strata. Increasing the filtration velocity of the accumulated liquid to the engrossed formation will result; and periodical shut down of the well occurs during which the liquid drains back to the formation.
Third, there is the prevention of the liquid hydrocarbon filtration down to the bottomhole which will reduce the well exploitation rate down to a lower production rate. This will result in an insufficient bottomhole pressure, that will prevent the production of the liquid from the well formation. Thus, there will be an absolute or particular isolation of the source of the liquid production from the strata pay zone. To prevent this, a combination of the first and second recovery methods are used.
Despite the above described prior art methods, a need still exists for a device that is not only useful for liquid withdrawal purposes from a well but which also does not permit fluid to accumulate at the bottom of the well.
Attempts have been made in the past to solve these prior art problems, and prior proposals are as follows:
______________________________________ U.S. Pat. No. Date Patentee ______________________________________ 4,390,061 6/1983 Short 4,509,599 4/1985 Chenoveth et al. 4,678,040 7/1987 McLaughlin et al. 4,791,990 12/1988 Amani 5,006,046 4/1991 Buckman et al. 5,105,889 4/1992 Misikov et al. 5,302,286 4/1994 Semprini et al. 5,374,163 12/1994 Jaikaran 5,407,010 4/1995 Herschberger 5,547,021 8/1996 Raden 5,562,161 10/1996 Hisaw et al. ______________________________________
Other Publications
Gas Dynamics of Two-Phase Flows, M. Deich, G. Phillippov. Energy Publishing House, Moscow, 1968, pp. 206-292.
Production, Treatment and Transportation of Natural Gas and Condensate, Volume 1, Y. Korotayev et al., Nedra Publishing House, Moscow, 1984, pp. 179-189, 337-355.
Two-phase Flow in Pipelines and Heat Exchangers. D. Chisholm, Lecturer in Thermodynamics and fluid Mechanics, Glasgow College of Technology, George Godwin, London and New York in association with The Institution of Chemical Engineers, 1983, pp. 133-196.
Hisaw et al. uses artificial gas injection, and not a natural flow of gases from within the well.